chore: organize solution into module folders (Core/Server/Drivers/Client/Tooling)

Group all 69 projects into category subfolders under src/ and tests/ so the
Rider Solution Explorer mirrors the module structure. Folders: Core, Server,
Drivers (with a nested Driver CLIs subfolder), Client, Tooling.

- Move every project folder on disk with git mv (history preserved as renames).
- Recompute relative paths in 57 .csproj files: cross-category ProjectReferences,
  the lib/ HintPath+None refs in Driver.Historian.Wonderware, and the external
  mxaccessgw refs in Driver.Galaxy and its test project.
- Rebuild ZB.MOM.WW.OtOpcUa.slnx with nested solution folders.
- Re-prefix project paths in functional scripts (e2e, compliance, smoke SQL,
  integration, install).

Build green (0 errors); unit tests pass. Docs left for a separate pass.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

tests/Server/ZB.MOM.WW.OtOpcUa.Admin.Tests/AdminRolesTests.cs

@@ -0,0 +1,18 @@
+using Shouldly;
+using Xunit;
+using ZB.MOM.WW.OtOpcUa.Admin.Services;
+
+namespace ZB.MOM.WW.OtOpcUa.Admin.Tests;
+
+[Trait("Category", "Unit")]
+public sealed class AdminRolesTests
+{
+    [Fact]
+    public void All_contains_three_canonical_roles()
+    {
+        AdminRoles.All.Count.ShouldBe(3);
+        AdminRoles.All.ShouldContain(AdminRoles.ConfigViewer);
+        AdminRoles.All.ShouldContain(AdminRoles.ConfigEditor);
+        AdminRoles.All.ShouldContain(AdminRoles.FleetAdmin);
+    }
+}